Elastic Load Balancing has added new CloudWatch metrics to provide you with more insight into the state of your back-end instances and applications.

The following new metrics are now available:

Backend Connection Errors: the number of errors encountered by the load balancer while attempting to connect to your application.

Surge Queue Length: the number of requests queued by the load balancer, awaiting a back-end instance to accept connections and process the request.

Spillovers: the number of rejected requests due to a full surge queue.

These new metrics help you understand if your application is appropriately scaled and performing correctly. For example, an increase in the surge queue length indicates that your application is unable to service the incoming request volume. Spillovers occur when no more requests can be queued, alerting you to a potential problem with your application that requires investigation.